Bridge floor and wear plate therefor



y 1966 H. s. NAGIN 3,253,289

BRIDGE FLOOR AND WEAR PLATE THEREFOR Filed April 5, 1963 INVENTOR. QHARRY S. NAGIN.

ATTORNEYS.

United States Patent 3,253,289 BRIDGE FLOOR AND WEAR PLATE THEREFORHarry S. Nagin, Merion, Pa., assignor to Reliance Steel ProductsCompany, McKecsport, Pa., a corporation of Pennsylvania Filed Apr. 3,1963, Ser. No. 270,340 8 Claims. (CI. 1473) This invention relates tobridge floors, and particularly highway bridge boors is for an improvedfloor construction and wear plate for application to bridge floors.

The invention is applicable either to new floors or for the repair ofexisting floors and for purpose of illustration and not by way ofexclusion, it will be hereinafter described particularly for the repairof existing flooring.

Lightweight bridge floors are commonly comprised of panels of opengrating made of parallel main bearing bars connected by cross barsextending crosswise of the hearing bars and welded thereto. Often thebearing bars which are several inches in depth are of modified I-beamsection while the cross bars are usually rectangular bar sections. Inmany cases, the cells formed by the grating may be filled with concreteinstead of being completely open. r

Under conditions of heavy trafiic the bars may wear smooth and increasethe tendency of a car to skid. This may be corrected to a considerableextent by notching the edge of the grating bars in a well-known manner,but in time these notches also become smooth, polished and worn. Whenthis occurs the grating may have to be replaced, which is expensive andinterferes with traffic. Where the floor is a grating filled withconcrete, not only does the grating wear, but the concrete becomescupped.

While it has been proposedto repair such floors by applying checkerplates thereto, these wear smooth quite rapidly and a problem isinvolved in securing them in place. Also, while it has been proposed tocover such plates with a composition of resin and coarse abrasiveaggregate, a greater problem is involved in securing them over thegrating because of the destructive action of the heat of welding on theresin-abrasive coating.

The present invention provides an anti-skid surfacing plate applicableto bridge floor gratings which is of unique construction and which canbe applied to the grating securely and rapidly by workmen working on topof the bridge floor and without damage to the anti-skid surfacingmaterial. The invention further provides a novel bridge fioor in whichthe surfacing plate integrates the grating so that if, as frequentlyhappens, imperfect welds have broken or loosened, it is effectuallyrepaired.

According to the preferred form of the invention a metal plate of thedesired size and thickness is provided with opposed downwardly-slopedintegral lugs that converge toward each other but the terminals of whichare spaced sufficiently to snuggly receive the top edge of a gratingbar. These pairs of lugs are located at intervals over the surface ofthe plate at places where they may straddle the bars of one set andavoid the intersections of the two sets of bars. Since bridge floorgratings are of generally uniform construction, the plates can bepunched to provide the lugs at a manufacturing plant with assurance thatthey may be taken from stock and fitted to the grating in the field. Theplates then have the surface covered with a mixture of aggregate,preferably coarse hard abrasive grains and a resin which is cured insitu, as for example aluminum oxide grains and epoxy resin with orwithout extenders or copolymers such as road oil, pine oil or polyamidesor combinations thereof.

In the drawings:

FIG. 1 is a section in perspective showing a fragment of a bridge floorembodying this invention;

' 3,253,289 Patented May 31, 1966 FIG. 2 is an end elevation of FIG. 1;

FIG. 3 is an enlarged fragmentary plan view of a single punched-out areaof the plate and a portion of the margin;

FIG. 4 is a transverse section in the plane of line IVIV of FIG. 3; and

FIG. 5 is a top plan view of a plate.

Referring in detail to the drawing, 2 designates a conventional form ofa light open grate bridge floor having main modified I-beam sectionbearing bars 3 and cross bars 4. Load-distributing bars below theneutral axis are indicated at 5. In this particular grating the I-beambearing bars have a narrow ridge 6 along the top, but in other forms ofgratings the bearing bars may have just a plain bar section, similar tobut of greater depth than the cross bars. The grating per se may be oneof many forms and per se foams no part of this invention.

According to this invention the grating has its area, or the trafficlanes of its area, covered with wear plate units 7. These plates may bemade in standard sizes so that each one, or even multiples thereof, cangenerally be used in most bridge floors. If, for example, the platesextend crosswise of the length of the bridge and the bridge provides twotwelve-foot trafiic lanes, two such plates each twelve feet in lengthand perhaps three feet wide may be placed end to end, and of coursesimilar plates are arranged side by side to provide a complete deck.This is merely indicative of one size and manner of placing the platesand is in no Way to be construed as limiting the size of the plates ormanner of using them.

Each plate unit 7 comprises a rolled metal base plate 8 of the desiredsize for convenient handling and use in the field. Welded around themargins of the top surface of the plate is a narrow metal border strip9, which is a fraction of an inch wide and perhaps to A" thick ascompared to the plate 8 which may be several feet long and a few feetwide.

At predetermined locations over its area the plate has I-shaped slotspunched therethrough, providing clearance openings 10 at each end of twoconfronting lips 11. These lips 11 are bent downwardly as best seen inFIG. 4 so that the free confronting edges thereof are below the plane ofthe bottom of the sheet and are spaced from each other a distance justlarge enough to allow the top edge :of one of the grating bars, such asthe ridge 6 of the bearer bars, to easily but snuggly enter the spacebetween them. The punched areas are so located with reference to thegrating to which they are to be applied that when the plate is set onthe grating in the position in which it is intended to be used, thepairs of confronting downwardly-sloped lips 11 never coincide with theintersections of the two sets .of bars. They may be located to straddleeither the main bearer bars, as shown, or the cross bars, but withoutbeing additionally punched to provide three clearance openings 10 theyshould be spaced to avoid intersections. Since the size of the gratingsis pretty closely standardized, this positioning of the lips presents noproblem for shop production of the plates.

After the plates have been punched, and either before or after the lipshave been bent down and the marginal strips have been applied, thepunched-out areas are covered with preferably square expendable insertshaving a release coating thereon to which resin will not adhere, and theentire remaining area of the plate inside the border strips is filledwith a filling 12 of reactive resin with a catalyst or curing agent andhard abrasive aggregate and leveled off to the level of the marginstrips 9. The margin strips provide a surface to support a roll orstrike-off for leveling the mix to a uniform depth. The resin abrasivemix may then be cured at ambient temperatures if desired, but preferablyto increase shop capacity and accelerate curing of the resin. An epoxyresin produced from the reaction of bisphenol and epichlorohydrin whichis liquid at room temperature, a viscosity at 25 C. between 40 and 160poises, and an epoxide equivalent of 180-195 istypical of one such.resin and the curing agent or catalyst may be diethylenetriamine orother polyfunctional amine. The resin, if desired, may be combined witha polyamid resin especially used for copolymerization with epoxy resin.

The resin cures in situ on the metal plate and firmly bonds thereto. Itis hard, weatheraresistant, impact-resistant, and the abrasive grainsare dense in order to provide a long wear-resisting anti-skid surface.The marginal strips, while not necessary, are desirable to protect thecompleted units in handling and shipping and avoid attrition of theedges of the resin. Because the plates can be fabricated and the resinapplied at a central point of manufacture, the resin can be mixed andcured under most favorable conditions.

When the plates are shipped into the field for use, they are set on thebridge floor in the position in which they are to be used with eitherthe bearing bars or the tops of the cross bars projecting into thespaces between the opposing lugs or lips 11. The plates are then weldedto the bridge floor by flowing welding metal at 13 into the valleysbetween the sloping lips 11 and the top edges of the grating bars thatextend up betweenthem. Good strong welds can be made in this Way by aman standing on the plate and without access to the underside of thebridge floor at all. The welding not only secures the plate in place,but serves to integrate the grating bars with the plate so that if inthe area covered by the plate there are any loose bars, such loosenesscan have no detrimental effect.

After the Welding is completed, a small mass of resin and abrasivegrains of putty-like consistency may be troweled or applied over thewelds to completely fill the cavities left in the plates duringmanufacture with material similar to the main body of the fillingmaterial. This protects the welds from the weather and provides a smoothfloor area.

The floor can be quickly covered and put into use with a minimuminconvenience to traffic. Where the cells of the bridge floor gratingare filled with concrete, as is sometimes the case, the concrete may bechipped away at those places where the welds will occur so that theplates may be laid down as before and the exposed edges of the bars atthe proper locations may enter between the lugs 11.

While I have shown and described a preferred embodiment of my invention,various changes in the construction may be made within the contemplationof my invention and under the scope of the following claims.

I claim:

1. A wear plate for application to the grating of a bridge floor whereinthe grating has intersecting bearing bars and cross bars, said wearplate comprising a metal plate having a plurality of spaced pairs ofopposed lugs thereon, the lugs of each pair sloping downwardly from theplane of the plate at convergent angles and having confronting freelower ends that are spaced from each other a distance such as tostraddle the top edge of a grating bar when the plate is placed over thegrating, the area of the plate above the pairs of lugs being open toafford access to the lugs when the plate is placed over an area ofgrating for welding them to bars which they straddle, and means on thesurface of the plate providing a traction surface for vehicle wheels.

2. A wear plate for application to a traffic bearing grating havingintersecting bearing bars and cross bars, said wear plate comprising asheet metal plate adapted to set on and cover a predetermined area ofthe grating, said plate having a plurality of spaced pairs of opposedintegral lugs thereon, the opposed lugs of each pair sloping downwardlyat convergent angles from the plane of the sheet with confronting lowerends that are spaced to receive the top edges of grating bars betweenthem with the ends bearing against the sides of the bars below the topedges and provide between each lug and the bar which it engages a valleyin which welding metal may be retained, the pairs of lugs beingpositioned to engage the grating bars between the places where the barsintersect.

3. A wear plate for application to a grating as defined in claim 2 inwhich the plate is provided with a surfacing material of resin andabrasive grains adhered to the top surface thereof, the area of theplate above the lugs being free of the surfacing material.

4. A wear plate for application to a trafiic bearing grating as definedin claim 2 in which the top surface of the wear plate has marginalstrips welded thereto at its edges, and a layer of surfacing materialover the top surface confined Within the marginal strips and being atleast as deep as the thickness of the marginal strips, the surfacinglayer comprising a mixture of resin and coarse abrasive grains bonded insitu to the surface of the plate, the areas of the plate above saidpairs of lugs being free of the surfacing layer to afford access to thelips when the plate is to be welded to a grating.

5. The combination with a traffic bearing grating having bearing barsand intersecting cross bars, of a traffic bearing covering thereovercomprised of a wear plate covering an area of the grating comprehendingportions of several bearing bars and cross bars, the wear platecomprising a flat metal plate having pairs of integral opposed lugsstruck from the body of the plate and extending downwardly from theplate at convergent angles, the lugs of each pair terminating below theplane of the plate, the ends of the opposed lugs of each pair having thetop edge of a portion of a grating bar fitted therebetween with the lugswelded along the top ends of the lugs to said portions of the bars atintervals over the area of the plate, and means on the top of the plateproviding a traction surface thereover.

6. The combination defined in claim 5 wherein the traction surface isformed of a layer of resin and coarse abrasive material bonded in situto the top of the plate, the area of the plate above said lugs beingclear of said layer.

7. The combination defined in claim S Wherein the traction surface isformed of a layer of resin and coarse abrasive material bonded in situto the top of the plate, the area of the plate above said lugs beingclear of said layer, the areas of the plate above the lugs containing aseparately applied filling material that is substantially flush with thetop of said layer.

8. The combination defined in claim 5 wherein the traction surface isformed of a layer of resin and coarse abrasive material bonded in situto the top of the plate, the area of the plate above said lugs beingclear of said layer, each plate having a marginal metal strip on the topsurface thereof around its edges of the same thickness as said layer.

References Cited by the Examiner UNITED STATES PATENTS 598,557 5/1910Stiggleman 52584 1,845,693 2/ 1932 Wojciechowski 189-34 1,939,73212/1933 Stresau 52-483 2,360,933 10/1944 Bunker 52-496 2,960,919 11/1960Nagin 9430 FOREIGN PATENTS 914,611 7/1954 Germany.

CHARLES E. OCONNELL, Primary Examiner..

JACOB L. NACKENOFF, Examiner.

N. C. BYERS, Assistant Examiner.

1. A WEAR PLATE FOR APPLICATION TO THE GRATING OF A BRIDGE FLOOR WHEREINTHE GRATING HAS INTERSECTING BEARING BARS AND CROSS BARS, SAID WEARPLATE COMPRISING A METAL PLATE HAVING A PLURALITY OF SPACED PAIRS OFOPPOSED LUGS THEREON, THE LUGS OF EACH PAIR SLOPING DOWNWARDLY FROM THEPLANE OF THE PLATE AT CONVERGENT ANGLES AND HAVING CONFRONTING FREELOWER ENDS THAT ARE SPACED FROM EACH OTHER A DISTANCE SUCH AS TOSTRADDLE THE TOP EDGE OF A GRATING BAR WHEN THE PLATE IS PLACED OVER THEGRATING, THE AREA OF THE PLATE ABOVE THE PAIRS OF LUGS BEING OPEN TOAFFORD ACCESS TO THE LUGS WHEN THE PLATE IS PLACED